The present invention relates to a control system for a boom crane, wherein the boom crane has a tower and a boom pivotally attached to the tower, a first actuator for creating a luffing movement of the boom, and a second actuator for rotating the tower. The crane further has first means for determining the position rA and/or velocity {dot over (r)}A of the boom head by measurement and second means for determining the rotational angle φD and/or the rotational velocity {dot over (φ)}D of the tower by measurement. The control system for the boom crane controls the first actuator and the second actuator of the crane.
Such a system is for example known from DE 100 64 182 A1, the entire content of which is included into the present application by reference. There, a control strategy for controlling the luffing movement of the boom is presented, which tries to avoid swaying of the load based on a physical model of the load suspended on the rope of the crane and the crane itself. The model used is however only linear and therefore does not take into account the important non-linear effects observed in boom cranes. As the centrifugal acceleration of the load due to the rotation of the tower can also lead to swaying of the load, a pre-control unit tries to compensate it using data for the rotation of the crane based on the desired tangential movement of the load given by a reference trajectory generator as an input. However, these data based on the reference trajectories used in the pre-control unit can differ considerably from the actual movements of the crane and therefore lead to an imprecise control of the movements of the load and especially to a poor anti-sway-control.
From DE 103 24 692 A1, the entire content of which is included into the present application by reference, a trajectory planning unit is known which also tries to avoid swaying of the load suspended on a rope. However, the same problems as above occur, as the entire trajectory planner is based on modelled data and therefore again acts as a pre-control system.